1. Industrial Field of the Invention
The present invention relates to a method of mounting a component in which the component, such as a semiconductor chip, is thermally press-bonded onto a substrate with a conductive adhesive, such as anisotropic conductive adhesive. The present invention also relates to a method of producing an electro-optical device.
2. Description of the Related Art
A technology for mounting a component, such as a semiconductor chip, onto a glass substrate of, for example, a liquid crystal panel by a thermal press-bonding operation using anisotropic conductive film (ACF) is known. In this technology, by applying heat and pressure to the component while the anisotropic conductive film is sandwiched between the substrate and the component, resin contained in the anisotropic conductive film is set in order to bond the component to the substrate. Here, using the conductive particles contained in the anisotropic conductive film, a terminal on the substrate and a terminal of the component are electrically connected together.
However, in the mounting process using anisotropic conductive film, since the component is heated during the thermal press-bonding operation, the residual stress remaining after cooling, that is, after mounting the component onto the substrate may result in less reliable mounting. In addition, in order to electrically connect the terminal on the substrate and the terminal of the component with high reliability, it is necessary to sandwich a sufficient number of conductive particles between the terminals. In order to achieve this, it is necessary to properly control the flow of the anisotropic conductive film which is melted during the thermal press-bonding operation.
Accordingly, it is an object of the present invention to provide a component mounting method which makes it possible to more reliably mount a component using a conductive adhesive such as an anisotropic conductive film. It is also an object of the present invention to provide a method of producing an electro-optical device.
According to a first aspect of the present invention, there is provided a method of mounting a component in which the component is thermally press-bonded onto a substrate with a conductive adhesive. The method comprises the steps of: heating the substrate to a temperature which is 20xc2x0 C.xcx9c40xc2x0 C. below the glass transition point of a bonding resin contained in the conductive adhesive; and thermally press-bonding the component with the conductive adhesive onto the substrate heated to the aforementioned temperature.
According to this method of mounting a component, after the substrate has been heated to a temperature which is 20xc2x0 C. 40xc2x0 C. below the glass transition point of the bonding resin contained in the conductive adhesive, the component is thermally press-bonded onto the substrate with the conductive adhesive, so that the difference between the temperature of the component and that of the substrate when the component is thermally press-bonded during the press-bonding step can be decreased. Therefore, residual stress remaining after the mounting of the component can be decreased. In addition, since, in the thermal press-bonding operation, the substrate is heated, causing the temperature of the conductive adhesive to increase, the viscosity of the conductive adhesive during the thermal press-bonding step is sufficiently decreased, so that the conductive adhesive flows quickly. Consequently, the conductive particles contained in the conductive adhesive tend to remain between the terminal of the component and the terminal on the substrate, making it possible to more reliably electrically connect both of the terminals.
According to another aspect of the present invention, there is provided a method of mounting a component in which the component is thermally press-bonded onto a substrate with a conductive adhesive. The method comprising the steps of temporarily press-bonding the component onto the substrate with the conductive adhesive; heating the substrate to a temperature which is 20xc2x0 C.xcx9c40xc2x0 C. below the glass transition point of a bonding resin contained in the conductive adhesive while the component is temporarily press-bonded onto the substrate; and thermally press-bonding the component with the conductive adhesive onto the substrate heated to the aforementioned temperature.
According to this method of mounting a component, after the substrate has been heated to a temperature which is 20xc2x0 C. to 40xc2x0 C. below the glass transition point of the bonding resin contained in the conductive adhesive, the component is thermally press-bonded onto the substrate with the conductive adhesive, so that the difference between the temperature of the component and that of the substrate when the component is thermally press-bonded during the press-bonding step can be decreased. Therefore, residual stress remaining after the mounting of the component can be decreased. In addition, since, in the thermal press-bonding operation, the substrate is heated, causing the temperature of the conductive adhesive to increase, the viscosity of the conductive adhesive during the thermal press-bonding step is sufficiently decreased, so that the conductive adhesive flows quickly. Consequently, the conductive particles contained in the conductive adhesive tend to remain between the terminal of the component and the terminal on the substrate, making it possible to more reliably electrically connect both of the terminals.
The step of heating the substrate may comprise heating the substrate to a temperature which is 25xc2x0 C.xcx9c35xc2x0 C. below the glass transition point of the conductive adhesive.
The step of heating the substrate may comprise heating the substrate to the aforementioned temperature by heating a receiving table on which the substrate is placed.
The conductive adhesive may contain thermosetting resin and conductive particles mixed in the thermosetting resin.
A semiconductor chip used as the component may be mounted on a glass substrate used as the substrate.
The glass substrate may form a liquid crystal device.
The glass transition point of the conductive adhesive may lie in a range of from 80xc2x0 C. to 130xc2x0 C.
According to still another aspect of the present invention, there is provided a method of producing an electro-optical device having a pair of opposing substrates. The method comprises the step of mounting a semiconductor chip onto at least one of the substrates with an anisotropic conductive film. The step of mounting a semiconductor chip comprises the steps of heating one of the substrates to a temperature which is 20xc2x0 C. to 40xc2x0 C. below the glass transition point of a bonding resin contained in the anisotropic conductive film; and thermally press-bonding the semiconductor chip with the anisotropic conductive film onto the substrate heated to the aforementioned temperature.
For the sake of easier understanding of the present invention, brackets are added to reference numerals and characters in the attached drawings. However, the present invention is not limited to the forms of the component parts illustrated in the figures.